141 lines
4.3 KiB
C
141 lines
4.3 KiB
C
/* Open a descriptor to a file.
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Copyright (C) 2007-2008 Free Software Foundation, Inc.
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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/* Written by Bruno Haible <bruno@clisp.org>, 2007. */
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#include <config.h>
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/* Get the original definition of open. It might be defined as a macro. */
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#define __need_system_fcntl_h
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#include <fcntl.h>
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#undef __need_system_fcntl_h
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#include <sys/types.h>
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static inline int
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orig_open (const char *filename, int flags, mode_t mode)
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{
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return open (filename, flags, mode);
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}
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/* Specification. */
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#include <fcntl.h>
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#include <errno.h>
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#include <stdarg.h>
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#include <string.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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int
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open (const char *filename, int flags, ...)
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{
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mode_t mode;
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int fd;
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mode = 0;
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if (flags & O_CREAT)
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{
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va_list arg;
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va_start (arg, flags);
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/* If mode_t is narrower than int, use the promoted type (int),
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not mode_t. Use sizeof to guess whether mode_t is narrower;
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we don't know of any practical counterexamples. */
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mode = (sizeof (mode_t) < sizeof (int)
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? va_arg (arg, int)
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: va_arg (arg, mode_t));
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va_end (arg);
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}
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#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
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if (strcmp (filename, "/dev/null") == 0)
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filename = "NUL";
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#endif
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#if OPEN_TRAILING_SLASH_BUG
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/* If the filename ends in a slash and one of O_CREAT, O_WRONLY, O_RDWR
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is specified, then fail.
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Rationale: POSIX <http://www.opengroup.org/susv3/basedefs/xbd_chap04.html>
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says that
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"A pathname that contains at least one non-slash character and that
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ends with one or more trailing slashes shall be resolved as if a
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single dot character ( '.' ) were appended to the pathname."
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and
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"The special filename dot shall refer to the directory specified by
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its predecessor."
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If the named file already exists as a directory, then
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- if O_CREAT is specified, open() must fail because of the semantics
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of O_CREAT,
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- if O_WRONLY or O_RDWR is specified, open() must fail because POSIX
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<http://www.opengroup.org/susv3/functions/open.html> says that it
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fails with errno = EISDIR in this case.
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If the named file does not exist or does not name a directory, then
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- if O_CREAT is specified, open() must fail since open() cannot create
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directories,
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- if O_WRONLY or O_RDWR is specified, open() must fail because the
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file does not contain a '.' directory. */
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if (flags & (O_CREAT | O_WRONLY | O_RDWR))
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{
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size_t len = strlen (filename);
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if (len > 0 && filename[len - 1] == '/')
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{
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errno = EISDIR;
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return -1;
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}
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}
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#endif
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fd = orig_open (filename, flags, mode);
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#if OPEN_TRAILING_SLASH_BUG
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/* If the filename ends in a slash and fd does not refer to a directory,
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then fail.
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Rationale: POSIX <http://www.opengroup.org/susv3/basedefs/xbd_chap04.html>
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says that
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"A pathname that contains at least one non-slash character and that
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ends with one or more trailing slashes shall be resolved as if a
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single dot character ( '.' ) were appended to the pathname."
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and
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"The special filename dot shall refer to the directory specified by
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its predecessor."
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If the named file without the slash is not a directory, open() must fail
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with ENOTDIR. */
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if (fd >= 0)
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{
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size_t len = strlen (filename);
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if (len > 0 && filename[len - 1] == '/')
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{
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struct stat statbuf;
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if (fstat (fd, &statbuf) >= 0 && !S_ISDIR (statbuf.st_mode))
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{
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close (fd);
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errno = ENOTDIR;
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return -1;
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}
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}
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}
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#endif
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#ifdef FCHDIR_REPLACEMENT
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if (fd >= 0)
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_gl_register_fd (fd, filename);
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#endif
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return fd;
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}
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